September 2017 is the 44th month of the PlayStation 4 being on sale in Japan. The gap grew in favor of the PlayStation 4 by 32,176 units in the last month and in favor of the PlayStation 4 by 33,874 units in the last 12 months. The PlayStation 4 currently leads by just 15,536 units.
The PlayStation 3 launched in November 2006, while the PlayStation 4 launched in February 2014. The PlayStation 4 has sold 5.35 million units, while its predecessor the PlayStation 3 sold 5.33 million units.